FreeSWITCH
5.2kScalable open source cross-platform telephony platform.
Communication - SIPMPL-2.0
Full-featured IPBX solution built atop Asterisk with integrated Web administration interface and REST-ful API.
Scalable open source cross-platform telephony platform.
Easy to use but advanced IP PBX system, VoIP gateway and conference server.
Modular SIP server (registrar/proxy/router/etc).
Troubleshooting and monitoring VoIP calls.
Lightweight SIP proxy, location server, and registrar for a reliable and scalable SIP infrastructure.
SIP proxy/server for voice, video, IM, presence and any other SIP extensions.